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Thread: How about a nice 350x 502cc big bore kit?

  1. #1
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    How about a nice 350x 502cc big bore kit?

    I know there were some guys building some big 350x 's on here years ago but they had big dome piston with super high compression that looked like rod breakers to me. I'm building a 502cc kit to run a big cam but on pump gas and I was wanting some feed back if those guys motors stayed together, or if anyone had one them selves and what they thought about them.

  2. #2
    xrider is offline Got The Holeshot Arm chair racerJust too addicted
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    There have been tons of setups over the years. The more recent I remember was a 492cc big bore that a member was offering a while back (96mm bore I believe). Another popular one was the Ascott 500 head setup. I can't help you out much on the really big cc motors out there. I am running the 425cc kit that you used to offer in my 350x and it has been bullet proof so far. Easy to start with the FCR carb and 40 hp on tap.

  3. #3
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    Quote Originally Posted by xrider View Post
    There have been tons of setups over the years. The more recent I remember was a 492cc big bore that a member was offering a while back (96mm bore I believe). Another popular one was the Ascott 500 head setup. I can't help you out much on the really big cc motors out there. I am running the 425cc kit that you used to offer in my 350x and it has been bullet proof so far. Easy to start with the FCR carb and 40 hp on tap.
    Well I know about using the Ascot head because I did a magazine article on that back in the 90's in Dirt Wheels. I have built about every bore and stroke combo over the years and I like flat top big pistons with the small combustion chamber of the 350x that keeps a good quench area around the out side of the piston with a short flame travel and light weight pistons. This is easy on the rod and keep the reliability and longevity we all like our Honda's for in the first place.

  4. #4
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    My buddy has one in a pulling bike that is bored and stroked to 502 with a turbo on it now and it has held up for a long time now it's been turbo charged for a year or so with no problems yet and was n/a for probley 10 year with no problems other than clutch issues.
    If its on the internet its got to be true they can't put any lie's on the internet

  5. #5
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    sounds like an awesome idea Mickey. would be an awesome setup for an MX or CX motor.
    ________________
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    Nearly every kind of Honda ATC (plus some custom ones
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    "Freedom is not free...but the U.S. Marine Corps will pay most of your share."

  6. #6
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    Quote Originally Posted by big specht View Post
    My buddy has one in a pulling bike that is bored and stroked to 502 with a turbo on it now and it has held up for a long time now it's been turbo charged for a year or so with no problems yet and was n/a for probley 10 year with no problems other than clutch issues.

    How much boost, and was it a stock rod? Compression ratio?

  7. #7
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    Quote Originally Posted by oscarmayer View Post
    sounds like an awesome idea Mickey. would be an awesome setup for an MX or CX motor.
    They are coming. Now I have to go buy a 350x too. lol More because of the new fenders I'm making, they look so cool on the 350x.

  8. #8
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    Quote Originally Posted by Mickey Dunlap View Post
    How much boost, and was it a stock rod? Compression ratio?
    Not sure on compression ratio. It's a 9mm poweroll stroker. As for boost I'm not sure where it's at now but I'm pretty sure it's between 10 to 15psi (we know it's a time bomb)
    If its on the internet its got to be true they can't put any lie's on the internet

  9. #9
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    Quote Originally Posted by Mickey Dunlap View Post
    They are coming. Now I have to go buy a 350x too. lol More because of the new fenders I'm making, they look so cool on the 350x.
    They'll look even cooler when they're flying by on a 350x with one of your big bore kits!

  10. #10
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    How much H.P increase over stock would this "502" be? One of my 350x's is in dire need of a rebuild and I might go in the direction of a big bore.
    YAMAHA 450 HYBRID
    85 350X- RED
    85 350x -BLACK
    86 350x-WHITE (with Goki)
    85 250r
    83 atc 70
    84 atc 70
    84 atc 110
    09 yfz 450
    2006 Arctic Cat Prowler
    RZR XP 900

  11. #11
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    well I am getting a 2nd 350x soon, if you want, I am willing to work out a deal. you use it as a test model for a couple of months or so and do the stuff you want. that saves you the $ on buying the 350x. ya just pay for shipping.
    ________________
    I'm just a squirrel "Trying" to get a nut!

    Nearly every kind of Honda ATC (plus some custom ones
    several Yami Quads (mostly custom built for MX racing)

    https://www.mikesatvfix.com

    "Freedom is not free...but the U.S. Marine Corps will pay most of your share."

  12. #12
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    Quote Originally Posted by BOB MARLIN View Post
    How much H.P increase over stock would this "502" be? One of my 350x's is in dire need of a rebuild and I might go in the direction of a big bore.
    With the new cams and head work, carb and good pipe it's over 50 with the smaller motors I have been building, but most won't do all that so I'll just put the kit with a cam and a 400ex carb and dyno it the way most will build them.

  13. #13
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    Quote Originally Posted by oscarmayer View Post
    well I am getting a 2nd 350x soon, if you want, I am willing to work out a deal. you use it as a test model for a couple of months or so and do the stuff you want. that saves you the $ on buying the 350x. ya just pay for shipping.
    I have had a few of those offers but I think I would like to build one for my self with the right set up to go fast, cut tank, long swing arm and of coarse low fenders.

  14. #14
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    Have you set a time frame on when this might happen ?.
    YAMAHA 450 HYBRID
    85 350X- RED
    85 350x -BLACK
    86 350x-WHITE (with Goki)
    85 250r
    83 atc 70
    84 atc 70
    84 atc 110
    09 yfz 450
    2006 Arctic Cat Prowler
    RZR XP 900

  15. #15
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    sweet! ok sounds good sir.
    ________________
    I'm just a squirrel "Trying" to get a nut!

    Nearly every kind of Honda ATC (plus some custom ones
    several Yami Quads (mostly custom built for MX racing)

    https://www.mikesatvfix.com

    "Freedom is not free...but the U.S. Marine Corps will pay most of your share."

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